A propeller of a turbo propeller gas turbine engine is mounted on a shaft supported by bearings to allow rotation of the shaft relative to its longitudinal axis and to transfer the torque from the engine to the propeller. The shaft is coupled to the propeller at one end and is drivingly engaged by a gearbox at an opposite end. The bearings are spaced apart from one another along an axial length relative to the shaft longitudinal axis. The axial length is referred to as a bearing span. The greater is the bearing span, the smaller are the loads transmitted from the propeller to the housing supporting the shaft.
However, increasing the bearing span usually results in an increase of an overall length of the gas turbine engine. Engine performances are directly impacted by the overall length and as such it is a design objective to reduce the overall length of the gas turbine engine. Therefore, the gain associated with an increase of the bearing span may be overshadowed by the performance loss imputed to the increase in engine overall length.